Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Compact heat-generating devices, such as integrated-circuits (including microprocessors, graphics chips, memory chips, radio frequency (RF) chips, networking communication chips, microwave chips, navigation chips, etc.), laser diodes, light-emitting diodes (LEDs), vertical-cavity surface emitting lasers (VCSELs) and the like, generate thermal energy, or heat, when in operation. Compact heat-generating devices may function as, for example, sensors or application-specific IC (ASIC) drivers in a telecom router, cellular phone tower, data communications server or mainframe computers. Regardless of which type of heat-generating device the case may be, heat generated by a compact heat-generating device needs to be removed or dissipated from the compact heat-generating device in order to achieve optimum performance of the compact heat-generating device by keeping its temperature within a safe operating range. With the form factor of compact heat-generating devices and the applications they are implemented in becoming ever smaller (e.g., the processor in a smartphone, a tablet computer or a notebook computer) and thus resulting in high heat density, it is imperative to effectively dissipate the high-density heat generated in an area of a small footprint to ensure safe and optimum operation of compact heat-generating devices operating under such conditions.
As compact heat-generating devices such as microprocessors, graphics chips, memory chips, etc. are typically mounted on a printed circuit board (PCB) inside an electronic apparatus (e.g., a portable device), the PCB itself often acts as a heat sink and/or heat spreader since at least part of the heat generated by a heat-generating device mounted on a PCB can be transferred from the heat-generating device to the PCB, e.g., by conduction through the direct contact(s) between the heat-generating device and the PCB. However, when there are more than on heat-generating devices mounted on the same PCB, have the PCB acting as a heat sink and/or heat spreader is not ideal as heat absorbed by the PCB from one heat-generating device tends to lower the thermal gradient in the PCB, thus lowering the amount of heat transferred to the PCB from another heat-generating device that is also mounted on the PCB. Worse, it may be possible that heat transferred from one heat-generating device is transferred to another heat-generating device through the PCB. In other words, when multiple heat-generating devices are mounted on the same PCB, thermal coupling between/among two or more of the multiple heat-generating devices through the PCB may occur, thus negatively impacting heat transfer away from one or more of the heat-generating devices to result in degradation in the performance and shortening of lifetime of the affected heat-generating devices.